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Currently, the Republic of Korea is investigating an outbreak of a pathogen that’s far from home: Middle East Respiratory Syndrome (MERS). As of June 11, 2015, there have been up to 121 known MERS cases in Korea, resulting in nine deaths. The outbreak has been concentrated around hospitals, which are acting as epidemiological epicenters of MERS transmission.

The concentration of cases within hospitals has caused the government of Korea to publicly name 24 MERS-affected hospitals, presumably to provide the public with information about which ones are safe to use if needed. The government has also closed over two thousand schools and nineteen universities in an attempt to limit the spread of the virus. Additionally, almost three thousand citizens of Korea are in quarantine.

Though this outbreak has been receiving a fair amount of news coverage, the CDC does not advise Americans to change travel plans that include Korea at this time.

Middle East Respiratory Syndrome (MERS) is caused by a coronavirus called MERS-CoV. Coronaviruses are a common type of virus, named because they have viral spikes that protrude from their surface, making them resemble crowns when viewed under an electron microscope. Most people will get infected by some form of a coronavirus at some time in their lives—it is thought that a large percentage of common colds are caused by coronaviruses, which typically infect the upper respiratory and digestive tracts of mammals or birds.

There are, however, some more serious infections also caused by these viruses, including MERS and Severe Acute Respiratory Syndrome (SARS). Just as there is no vaccine for the common cold, there is no vaccine currently available for MERS. Researchers believe that MERS likely entered the human population via dromedary camels in Saudi Arabia, in a scenario similar to the Ebola virus’ links to human contact with bats and primates in Zaire, now the Democratic Republic of Congo.

The typical symptoms of MERS include fever, cough, and shortness of breath. It can also cause digestive problems, such as diarrhea, nausea, and vomiting. Some MERS patients become susceptible to severe complications, such as pneumonia or kidney failure. The CDC reports MERS is typically fatal in approximately three to four patients out of every 10, though those who die typically suffer from an underlying medical condition, such as cancer or chronic diseases of the lung, heart, or kidney. The fatality rate in the current outbreak is not as high as this, and some infected persons only report mild cold symptoms or are asymptomatic.

MERS is communicated from close contact with infected individuals. Like most respiratory illnesses, it’s spread via an infected individual’s respiratory secretions. In other words, when infected individuals cough or sneeze, they produce airborne globules that can spread the virus, though the precise mechanisms of transmission are not yet well understood.

The virus is usually spread from an infected person to those caring for them or living with them. The CDC estimates that the incubation period for MERS is typically five to six days, though it could range as widely as two to 14 days.

The CDC says that the risk of MERS infection in the US is currently very low, as the last reported case here was over a year ago (in May 2014). As a precautionary measure, surveillance for the presence of MERS in our healthcare system is underway, but this is no cause for alarm. Healthcare surveillance is a standard first-line defense during outbreaks, and the presence of surveillance for MERS doesn’t indicate anything other than a very low risk of MERS infection in the US.

The current outbreak of MERS is much smaller and more contained than the recent outbreak of Ebola in West Africa, and the government of Korea is taking strong measures to prevent its continued spread. For those concerned about possible MERS infection, the CDC simply suggests standard precautions, such as regular hand washing and avoiding contact with people who are ill.

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Roheeni Saxena
Roheeni is a Science Correspondent writing for Ars Technica. She holds an MPH from Columbia, where she worked as Associate Director of Educational Programs. She has also worked as a bench researcher for Harvard Medical School and the NIMH. She is currently pursuing a PhD in environmental health and neurotoxicology from Columbia. Emailroheeni.explains.science@gmail.com//Twitter@RoheeniSax